Connection devices for connecting a cable to a signal connector, and especially to a communication device, such as a computer, a notebook or a telephone, are commonly used in practical applications. In such applications, the plug connected to the cable is inserted into a corresponding socket of the electrical device.
Connection devices for electrical cables usually include an eight-pin plug, generally known as RJ-45 plug or Western plug, on the cable side and a corresponding socket on the equipment side. The plug is generally attached to cable using the crimp connection technique, but may also be soldered thereto. Usually, the plug is locked within the socket by a latching arm as it is inserted therein, but may also be retained by fastening hooks provided on the socket or on the electrical device, or may be screwed to the electrical device.
In addition, there are connection devices for optical cables, i.e., for optical waveguides. An optical waveguide is an optical device which is suitable for transporting light and is often formed of a multiplicity of individual glass fibers or plastic fibers, especially polymer fibers, which are very thin in relation to their length and which are combined into a bundle. In the following, the term “optical waveguide” will be understood to also include one having a single fiber. The individual glass fibers or plastic fibers are generally surrounded by a plastic jacket. Compared to electrical signals, the much higher carrier frequency of light allows more data to be transmitted in the same period of time, or the same amount of data to be transmitted in a shorter time than with conventional coaxial cables. Moreover, optical waveguides are free of EMC problems. Compared to glass fibers, polymer fibers have much higher attenuation values and larger diameters, but they are inexpensive and easier to install.
Due to the increasing use of optical waveguides, there is a growing demand for easy-to-use and quickly connectable connection devices for optical waveguides (fiber optic plugs).
Fiber optic connection technology uses a variety of standard connectors which are incompatible with each other. The standard fiber optic plugs most frequently used are the ST plug, the PC/FC plug, and the SC plug, the latter finding increasing application.
The SC plug is a polarized, push-pull type fiber optic plug of small dimensions and high packing density. This plug is square in configuration and can be used for multimode fibers and monomode fibers. This plug allows establishment of simplex, duplex and multiple connections. Due to its design, it can be nonrotatably connected to the corresponding socket and be automatically locked therein.
In order to release such a fiber-optic plug from the corresponding socket, it is necessary to pull the plug housing about 1 to 2 mm axially away from the socket. This produces the desired movement of the outer plug housing relative to the inner housing accommodating the ferrules, thereby releasing the mechanical interlock between the inner housing of the plug and the corresponding socket.
However, the disadvantage here is that the standard fiber-optic plugs can be used only to a very limited extent in a rough industrial environment.
German document DE 10 2006 000 702 A1 describes a connection device which provides reliable mechanical protection of the plug and the optical waveguide to be connected. To this end, the connection device is provided with an additional mechanical securing means in the form of a resilient latching means capable of absorbing and transferring large tensile forces.